<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <input type="text">



    <script>
        
let str = '   xin xiang   ';
console.log(str,'去掉全部端空格');
console.log(str.replace(/\s+/g, ''));
//--------------------------------------------
//          console.log(Boolean(''));  //false
//          console.log(Boolean('    ')); //true
//---------------------------------------------
//         //  var str='           '
//         // let aa= str.trim()    //去除空格
//---------------------------------------------
    </script>
</body>
</html>